The present invention relates generally to the art of food preparation, and, in particular, to the use of yeast in food. It also relates to the use of bioactive substances which are preferably protected before exposure to other food ingredients and/or animal feed ingredients and/or environmental conditions in or out of food products and/or animal feed products.
Yeast is a living organism which is sensitive to its surrounding environment. Exposure of yeast to, for example, moisture, can destabilize the yeast.
Producers of dry mix packages for bakery mixes experience the limitations of yeast in their dry mix packages. There is sufficient moisture in the flour and the other components in the dry mix package to eventually destabilize the yeast included in the package. Due to the presence of moisture, the yeast begins to activate and produce carbon dioxide while still in the package mix. As a consequence, when the package mix is ready to be used by the consumer, the level of activity of the yeast is insufficient to produce carbon dioxide required to fully expand the cell structure of the dough. Thus, since the dough does not adequately rise, the resulting baked product is organoleptically inferior to the consumer.
One approach to solve this problem is to have the yeast added directly by the consumer. However, this can lead to inconsistency, and erratic performance due to consumer mishandling and limitations of mixing apparatuses and preparation methods.
Another approach is to package the yeast separately in smaller sachets. Therefore, the yeast is separated from the remaining components of the dry mix package. Nevertheless, this is an expensive alternative due to the high packaging costs for small amounts of yeast per sachet. Furthermore, the cost of ensuring a sachet is deposited into each dry mix package substantially adds to the cost of the package mix.
An alternative method to increase the stability of the dry mix package is to dry all the components of the package, including the flour. However, this approach is not effective since the components of the package will eventually reabsorb moisture during storage, to a level that is damaging to the yeast.
U.S. Pat. No. 6,261,613 to Narayanaswamy et al. discloses encapsulating particles, such as yeast, in a fat in a beta prime form (i.e., triglyceride crystals having a blocky symmetry). The coating material can further contain emulsifiers such as those found in hydrogenated vegetable oil. However, the coating only allows release of the yeast in a limited temperature range of about 40xc2x0 C. to about 55xc2x0 C.
U.S. Pat. No. 6,251,478 B1 to Pacifico et al. discloses sensitive substances such as Lactobacillus, enzymes, and nutrients encapsulated in a lipid material. The lipid materials disclosed include mono-, di-, and triacylglycerols. However, control of the rate of release of the sensitive substance is not provided.
There is a need to control rate of release of bioactive substances, such as yeast. Depending on the end product desired (e.g., bread), one may require the yeast to be released immediately upon contact with, for example, water. In the alternate, some products may require the rate of release to be delayed for a period of time upon exposure to water, such as, for example, refrigerated dough.
Therefore, there is a need to control rate of release of bioactive substances, especially yeast, in the field of food preparation. It is thus an object of the present invention to provide a stabilized encapsulated yeast having a coating containing a emulsifiable lipid which offers, for example, abrasion resistance, stability in storage, and controlled release of yeast for use in food compositions and food products. It is also an object of the present invention to stabilize bioactive substances which are preferably stabilized, protected and have controlled release as explained above for use in food compositions, food products and/or animal feed products.
The present invention is based on applicants"" surprising discovery that the rate of release of a bioactive substance can be controlled by encapsulating the bioactive substance in a coating containing an emulsifiable lipid and an additive.
Applicants"" have also surprisingly discovered that encapsulated bioactive substance composites having a coating consisting essentially of one or more monoglycerides exhibit increased release of the bioactive substance upon exposure of the encapsulated composite to a solvent, such as water.
The present invention includes an encapsulated bioactive substance composite, particularly an encapsulated yeast composite, and compositions thereof, especially food composition and products therefrom. The present invention also includes a method for preparing food compositions and products using the unique composite.
The encapsulated yeast composite includes a core containing yeast and a coating which contains an emulsifiable lipid. The coating protects the yeast from destabilizing factors (e.g., solvents) and also provides controlled release of the yeast when the composite is exposed to a solvent. In a preferred embodiment, the solvent is an aqueous solvent, such as water.
The emulsifiable lipid is any lipid which emulsifies when exposed to a solvent, and has a melting point which allows the lipid to be a solid at typical storage temperatures. The emulsifiable lipid can be a vegetable or animal derived-lipid. In a preferred embodiment, the emulsifiable lipid is a monoglyceride.
In a preferred embodiment, the encapsulated bioactive substance composite contains yeast surrounded by a coating which consists essentially of one or more monoglycerides.
The yeast useful in the present invention is any dry yeast, including, for example, Saccharomyces cerevisiae. In a preferred embodiment, the yeast is INSTANT yeast. The minimum amount of yeast present in the composite is about 5% by weight of the composite, preferably about 30%, and more preferably about 50% by weight of the composite. The maximum amount of yeast present in the composite is about 95% by weight of the composite, preferably about 90%, and more preferably about 85% of the composite.
The food composition which contains the encapsulated yeast composite can be a dry mix package, or a frozen or refrigerated dough. In a preferred embodiment, the food composition is a dry mix package.
The food product includes the composite which is combined with other food ingredients. The combination is subjected to a solvent which releases the yeast. In a preferred embodiment, the addition of a solvent to the combination results in a dough. The dough can be proofed and baked to obtain a food product. Preferably, the food product is a bakery product, and more preferably, a bread product.
As a result of the present invention, yeast is provided which can tolerate storage conditions (e.g., moisture, elevated temperature, oxygen, etc.) encountered by food compositions, such as dry mix packages and doughs. The coating of the encapsulated composite protects the yeast from the environment and provides emulsification in a solvent without detracting from the abrasion resistance of the coating. The emulsification of the coating in a solvent allows for release of the yeast. The emulsification of the coating can be controlled by including additives with the emulsifiable lipid. Controlling emulsification of the coating allows the coating to protect the yeast in compositions such as frozen and refrigerated doughs.
Other bioactive substances which can be encapsulated and afforded protection and controlled release in accordance with the present invention include, for example, bacteria, preferably probiotics, enzymes, and nutrients, such as vitamins, minerals, and antioxidants.
In another embodiment, the invention relates to a method of controlling the rate of release of a bioactive substance from an encapsulated composite upon exposure to a solvent. The method comprises blending an emulsifiable lipid with an amount of one or more additives to obtain a blend; and coating the bioactive substance with the blend to form an encapsulated bioactive substance containing a core which contains the bioactive substance and a coating which contains the blend, wherein the emulsifiable lipid and additive are not the same, and wherein the rate of release of the bioactive substance from the encapsulated composite upon exposure to a solvent is decreased as the amount of additive is increased. In the alternative, the rate of release of the bioactive substance from the encapsulated composite upon exposure to a solvent is increased as the amount of additive is decreased.
In a further embodiment, the invention provides a method for controlling rate of release of a bioactive substance from an encapsulated composite upon exposure to a solvent. The method includes coating the bioactive substance with an amount of an emulsifiable lipid to form an encapsulated bioactive substance composite, wherein the rate of release of the bioactive substance from the encapsulated composite is decreased as the amount of emulsifiable lipid based on total weight of the encapsulated composite is increased. In the alternative, the rate of release of the bioactive substance from the encapsulated composite is increased as the amount of emulsifiable lipid based on total weight of the encapsulated composite is decreased.
As a result of the present invention, bioactive substances are provided which can tolerate storage conditions (e.g., moisture, heat, oxygen, etc.) encountered by food compositions, food products and/or animal feed products. The coating of the encapsulated composite protects the bioactive substance from the environment and provides emulsification in a solvent without detracting from the abrasion resistance of the coating. The emulsification properties of the coating in a solvent allows for controlled release of the bioactive substance in a food composition, food product, and/or animal feed products.
For a better understanding of the present invention, together with other and further advantages, reference is made to the following detailed description, and its scope will be pointed out in the claims.